In the context of anthropogenic global warming, unprecedented drought is expected to emerge over some regions where drought conditions exceed the variation range of the natural state. However, it is still unclear how the 1.5 °C and 2 °C warming targets proposed by the Paris Agreement will delay or even prevent the emergence of unprecedented drought. To illustrate the benefits of the two warming targets for mitigating drought conditions, this study investigated the time of emergence (TOE) of unprecedented meteorological drought as indicated by the Standardized Precipitation Evapotranspiration Index (SPEI) using the Coupled Model Intercomparison Project Phase 6 (CMIP6) model ensembles forced by 4 Shared Socioeconomic Pathways (SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5). In particular, the pattern of TOE is explored for 4 pseudo warming scenarios under which global mean surface temperature (GMST) increases by 1.5 °C, 2 °C, 3 °C, and 4 °C above pre-industrial levels, respectively. The results suggested that: (1) Under the 1.5 °C and 2 °C warming scenarios, unprecedented meteorological drought is anticipated to emerge over southern Africa, Arabian Peninsula, central Asia, Mongolia, southwestern South America, and western and eastern Australia. (2) Under the 3 °C and 4 °C warming scenarios, unprecedented meteorological drought will expand to western North America, the Amazon, and the Mediterranean. (3) The comparisons with the exposure under the 3 °C and 4 °C warming scenarios show that the aspirational 1.5 °C and 2 °C Paris Agreement warming targets can prevent at least 0.6 × 10 km of land area, 1.4 × 10 people, and 0.6 × 10 km of cropland area from suffering the emergence of unprecedented meteorological drought.

中文翻译：

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将全球气温升高限制在 2°C 以下能否防止出现前所未有的干旱？


在人为全球变暖的背景下，一些干旱条件超出自然状态变化范围的地区预计将出现前所未有的干旱。然而，目前尚不清楚《巴黎协定》提出的1.5℃和2℃升温目标将如何延缓甚至阻止前所未有的干旱的出现。为了说明两个变暖目标对缓解干旱状况的好处，本研究使用耦合模型比对项目第六阶段（CMIP6）调查了标准化降水蒸散指数（SPEI）所显示的前所未有的气象干旱的出现时间（TOE）由 4 个共享社会经济路径（SSP1–2.6、SSP2–4.5、SSP3–7.0 和 SSP5–8.5）强制的模型集成。特别是，探索了 4 种伪变暖情景下的 TOE 模式，在这些情景下，全球平均表面温度 (GMST) 分别比工业化前水平增加 1.5 °C、2 °C、3 °C 和 4 °C。结果表明：（1）在升温1.5℃和2℃情景下，非洲南部、阿拉伯半岛、中亚、蒙古、南美洲西南部、澳大利亚西部和东部地区预计将出现前所未有的气象干旱。 （2）在升温3℃和4℃情景下，前所未有的气象干旱将扩大到北美西部、亚马逊和地中海。 (3) 与3℃和4℃升温情景下的暴露比较表明，《巴黎协定》理想的1.5℃和2℃升温目标可以阻止至少0.6×10km的土地面积、1.4×10人，还有0.6×10平方公里的耕地面积出现了前所未有的气象干旱。